Site Latitude	45° 56' 42.36" N (45.94510 °N)	Go to interactive map
Site Longitude	90° 16' 23.52" W (-90.27320 °E)
Site Elevation	472.0 masl
Site code	LEF
Dataset	ch4_lef_tower-insitu_1_allvalid-396magl
Assimilated	Yes Switch to unassimilated subset
Data provider	Arlyn Andrews, NOAA GML, 325 Broadway R/GML-1, Boulder, CO 80305-3328, United States, and Ankur Desai, United States
Partner(s)	Dan Baumann, United States
Laboratory	NOAA Global Monitoring Laboratory, 325 Broadway, NOAA R/GML-1, Boulder, CO 80305-3328, United States University of Wisconsin, United States

(a) Time series of CH₄ mole fractions, both observed and simulated, at this CarbonTracker-CH4 observation site. The measured mole fractions (black circles) are plotted along with CarbonTracker-CH4 simulated values with prior fluxes (dark green circles), posterior-assimilated fluxes (blue circles), and posterior-withheld fluxes (yellow circles).

(b) The time series of model residuals, the difference between the measured and simulated mole fractions, for simulation with prior fluxes (dark green circles), posterior-assimilated fluxes (blue circles), and posterior-withheld fluxes (yellow circles).

(c) Summary statistics for model residuals from to . Residuals are defined as observed values minus simulated values. "Bias" is the mean of the residuals; "std. dev." is the standard deviation, and RMSE is root-mean-square error. All quantities are in ppb of CH4. The time period over which these quantities are computed is set by the graphs (a) and (b).

(d) Seasonal histograms of residuals

(d) Seasonal histograms of the residuals for this dataset. See caption for top figure for the definition of residuals. The left panel collects all residuals for each northern hemisphere summer (June through September); the right panel is the northern hemisphere winter (November through April). The tan color shows the histogram of the residuals themselves; the blue lines and statistics shown in blue text are a summary of the residuals interpreted as a normal distribution. For this assimilated dataset, the assumed model-data mismatch averaged over the seasonal span is shown in green (lines and text). The vertical scales are relative, determined by the number of observations and how tightly they are grouped, with the area under the histogram forced to unity.